Chapter 16. The Chi-Square Test
16.1 Introduction 293
16.2 Synopsis 293
16.3 Examples 295
16.4 Details & Notes 308
The chi-square test is used to compare two independent binomial proportions, p1 and p2. In the analysis of clinical data, the binomial proportion typically represents a response rate, cure rate, survival rate, abnormality rate, or some other 'event' rate as introduced in the previous chapter. Often, you want to compare such 'response' rates between a treated group and a parallel control group.
The chi-square test is an approximate test, which may be used when the normal approximation to the binomial distribution is valid (see Chapter 15). A popular alternative, Fisher's exact test (Chapter 17), is based on exact probabilities ...